Some conventional image printing apparatuses have a printing function capable of printing an image on the surface of a disc such as a CD-R. In general, an image printing apparatus having such printing function can realize printing on a disc by setting a disc to be printed on a dedicated disc tray and locating the disc at a print position within the apparatus.
Print data for printing an image on a disc is generated by, e.g., a host apparatus connected to the image printing apparatus. Even when a print area designation region (logical print area) 210 set by a printer driver installed in the host apparatus which performs print control for the image printing apparatus is the same as the physical print area of a disc tray 200, as shown in FIG. 8, not all image data corresponding to the print area designation region are printed in the entire physical print area of the disc tray 200, but only image data of a portion (printable region 201) corresponding to a disc to be printed is used for actual printing.
Part of image data generated by the host apparatus is rejected (not used for printing but discarded) on the basis of the positional relationship between the physical print area of the disc tray 200 and the print area designation region set by the printer driver.
In the example of FIG. 8, as for the rejection amount of image data which is unnecessary for printing and rejected, image data of characters E to M are actually printable image data, and image data of the remaining characters A to D and N are rejected out of image data of characters A to N generated by the printer driver, regardless of whether the reference is the top or bottom of the disc tray.
In a conventional image printing apparatus, the print area designation region (220 or 230) set by the printer driver may be longer than the physical print area of the disc tray 200, as shown in FIGS. 9 and 10. In the example of FIG. 9, when the top of the disc tray is set as a reference for calculating the rejection amount of image data, image data to be printed are image data of characters E to M, and image data of the remaining characters A to D and N to W are rejected. The print result is the same as that in FIG. 8.
To the contrary, in the example of FIG. 10, when the bottom of the disc tray is set as a reference for calculating the rejection amount of image data, image data to be printed are image data of characters N to V, and image data of characters A to M and W are rejected. The print result in FIG. 10 is, therefore, different from that in FIG. 8.
When the rejection amount is calculated using the top of the disc tray as a reference, the disc tray length (DISC_TRAY_LENGTH) must be stored as a fixed value in the image printing apparatus, and cannot cope with a change in disc tray specification (shape, print area, or the like).
To the contrary, when the rejection amount is calculated using the bottom of the disc tray as a reference, the rejection amount is calculated on the basis of a disc tray length (disc_tray_length) supplied from the printer driver, and can cope with a change in disc tray specification on the printer driver side.
As described above, the disc tray top reference and disc tray bottom reference for calculation of the rejection amount have merits and demerits. A conventional image printing apparatus can only cope with either reference.